Pseudomonas aeruginosa in Chronic Obstructive Pulmonary Disease Patients with Frequent Hospitalized Exacerbations: A Prospective Multicentre Study

Background: Pseudomonas aeruginosa (PA) is a common microorganism related to severe exacerbations in Chronic Obstructive Pulmonary Disease (COPD). However, their role in COPD patients with frequent hospitalized exacerbations (FHE) is not well described. Objectives: We aimed to determine prevalence, risk factors, susceptibility patterns and impact on outcomes of PA in COPD patients with FHE. Methods: Prospective observational multicentre study that included COPD patients with FHE. The cohort was stratified in 2 groups according to the presence or absence of PA isolation in sputum. Patients were followed up for 12 months. Results: We enrolled 207 COPD patients with FHE. In 119 patients (57%), a valid sputum culture was collected. Of them, PA was isolated in 21 patients (18%). The risk factors associated with PA were prior use of systemic corticosteroids (OR 3.3, 95% CI 1.2-9.7, p = 0.01) and prior isolation of PA (OR 4.36, 95% CI 1.4-13.4, p < 0.01). Patients with PA had an increased risk of having ≥3 readmissions (OR 4.1, 95% CI 1.3-12.8, p = 0.01) and higher PA isolation rate (OR 7.7, 95% CI 2.4-24.6, p < 0.001) during the follow-up period. In 14 patients (67%), PA was resistant to at least one antibiotic tested. PA persisted in the sputum in 70% of patients. Conclusions: The presence of PA was related to 3 or more readmissions during the 1-year follow-up and PA persisted in the sputum despite an appropriate antibiotic treatment. This finding suggested an important role of PA in the course of the disease of COPD patients with FHE.